The Australian Gas Regulators had concerns about gas piping using copper PressFit being installed on or under metal roofs, due to the very high temperatures that the product could be exposed to in summer. PressFit fittings for gas have a HNBR (Hydrogenated Nitrile Butadiene Rubber) elastomeric O-ring seal inside the fitting which does not have the same resistance to high temperatures as that of copper.
The results of a previous study over a 3 month period indicated that the current testing criteria for HNBR would be applicable for Australia.
Several of the manufacturers of the PressFit products requested a more extensive trial be conducted covering all seasons and conditions experienced in Australia and so this additional study was conducted for a period in excess of a year.
As with the previous trial, the temperature loggers were installed in twelve sites across selected Australian states and territories where extreme high temperature conditions can occur, in order to establish the maximum temperature a copper PressFit fitting could experience. At each site temperate data loggers were installed with the thermocouple located within samples of copper tube and placed above the metal roof. The temperature recorders were programmed to record temperature measurements every 20 minutes, starting in July 2015 and being completed by September 2016. Due to the data storage limitation of the loggers, the units had to be swapped over every 12-14 weeks for a fresh logger.
Objectives:
- Establish continuous temperature measurement over a 12 month period for the worst case installation conditions in each Australian state.
- To establish the maximum temperature experienced by copper tube and fittings located above a metal roof. This had been determined in the previous trial as being the worst case situation.
- To determine the exposure time the copper tube and fittings were subjected to at different temperature ranges. Primarily for how long was the material at the maximum temperature.
- Provide additional information to the manufacturers of the fittings concerning the environmental conditions experienced in Australia.
Please email ICA.Australia@copperalliance.asia for a copy of the document.